My thoughts from a user perspective are that a mandatory app store is only beneficial to me to the extent that it enforces one or more positive aspects in publi

My thoughts from a user perspective are that a mandatory app store is only beneficial to me to the extent that it enforces one or more positive aspects in published apps that could be expected to disappear due to profit motives if looser alternatives were available. The existence of such an option would seem to lead directly to most apps being exclusive to the cheapest and least stringent viable store (this doesn't seem to be the case for Google, but it is often suggested that it is hindered by factors like preventing automatic updates for apps from third party stores). I would not expect to have a choice of stores for a single app, or serious competition between stores on rule quality. That primarily leaves the question of what positive aspects are enforced by Apple's App Store in the first place, beyond the omnipresent operating system security model.